The Carbon Balance: Identifying Carbon Sinks

If a natural or artificial reservoir accumulates and stores carbon-containing chemical compounds for an indefinite period, then it lowers the concentration of CO2 in the atmosphere. If the amount absorbed is greater than the amount released, then the reservoir is scientifically classified as a carbon sink.

If trees undergo photosynthesis, then they pull carbon dioxide from the air to build their trunks and leaves. If the forest is adding more mass than it is losing through decay, then it is removing more carbon than it emits. Therefore, a growing forest is a sink, not a source, making the statement false.

If the concentration of CO2 is higher in the air than in the water, then the gas will naturally dissolve into the surface of the ocean. If tiny marine plants called phytoplankton use that carbon for growth, then the carbon is moved into the biological cycle of the sea. Therefore, the ocean acts as a massive storage unit.

If a material stores carbon underground for millions of years and is then burned, then it releases that stored carbon into the atmosphere as CO2. If a process adds more carbon to the atmosphere than it removes, then it is defined as a carbon source.

If trees are cut down and burned or left to rot, then the carbon stored in their wood reacts with oxygen and returns to the atmosphere as CO2. If the living trees are no longer there to absorb new carbon, then the balance shifts to a net release. Therefore, clearing forests turns a sink into a source.

If plants and animals die, then their remains are broken down by decomposers in the dirt. If this organic matter stays buried and becomes part of the soil structure, then the carbon is effectively "locked away" from the atmosphere. Therefore, healthy soil is a major reservoir for carbon.

If sources provide more CO2 than sinks can absorb, then the concentration of CO2 in the atmosphere must rise. If CO2 is a greenhouse gas that traps heat, then more CO2 will lead to more trapped thermal energy. Therefore, an imbalance leads to global warming.

If we look for the biological mechanism that powers most carbon sinks, we find a chemical reaction in green organisms. If these organisms take in light, water, and CO2 to make food, then they are the primary "pump" for moving carbon into the biological sink.

If we want to slow down climate change, then we must find ways to remove CO2 from the air. If we store that carbon in a way that prevents it from returning to the atmosphere for a long time, then we are "sequestering" it. Therefore, sequestration is the act of long-term storage.

If a volcano erupts, then it releases gases that were trapped deep inside the Earth's mantle. If these gases include large amounts of carbon dioxide, then the volcano is adding new carbon to the atmospheric cycle. Therefore, it is a natural carbon source.

If soil stays frozen year-round, then the organic matter inside it cannot decay. If the matter doesn't decay, the carbon stays trapped in the ice. However, if the ground warms and melts, then bacteria will begin to break down that matter, releasing CO2 and methane. Therefore, it is a sink that can transform into a source.

If we calculate the net balance of an area, we subtract the output from the intake. If the output (12) is greater than the intake (10), then the area is losing carbon to the atmosphere. Therefore, even though it has trees, this specific forest is a source.

If a location stores carbon for long periods (A, C, E), it is a sink. If the atmosphere (B) is where the carbon is being held as a gas, it is the "reservoir" we are trying to clear, not a sink itself. If a power plant (D) releases CO2, it is a source.

If we are studying the carbon cycle, then we need to measure how fast carbon moves from one place to another. If we calculate the amount of carbon moving from the air into the ocean per year, then we are measuring the carbon flux.

If natural systems like forests aren't enough to balance human emissions, then we may need technology. If these machines are designed to mimic the absorption of trees and store the gas underground, then they are referred to as artificial carbon sinks.

If phytoplankton at the surface die or are eaten, then their carbon-rich bodies sink toward the seafloor. If this carbon reaches the deep ocean, then it is removed from the atmosphere for centuries. This downward "rain" of organic matter is the biological pump.

If a plant grows in the spring and decays in the fall, then the carbon has moved through the system in one season. If this process repeats every year, then it is a fast or short-term cycle compared to the millions of years it takes to form coal. Therefore, the statement is true.

If carbon is released from rocks or the Earth's interior, then it is a geologic process. If limestone is broken down by rain or volcanoes vent gas from the mantle, then they are acting as sources of geological carbon.

If organic matter is submerged in water, then oxygen cannot reach the bacteria that cause decomposition. If decomposition is slowed or stopped, then the carbon stays in the ground instead of being released as gas. Therefore, wetlands store vast amounts of carbon in the form of peat.

If we want to know if atmospheric CO2 is rising or falling, then we must track all inputs and outputs. If we compare the total "income" (sinks) to the total "expenses" (sources), then we have calculated the budget. Therefore, it is a measure of the overall balance in the system.